WASHINGTON — President Joe Biden will observe next month’s 22nd anniversary of the worst terrorist attack on U.S. soil at an Alaska military base with service members and their families, the White House announced.

It will be the first time that a president has not attended any of the observances that have been held annually in New York City, Pennsylvania and Virginia, just outside Washington, according to an Associated Press review of media coverage of these events.

Biden will stop in Alaska for the 9/11 observance at Joint Base Elmendorf-Richardson in Anchorage on his way back to Washington after he attends a summit in New Delhi with other world leaders and visits Vietnam on Sept. 10.

Vice President Kamala Harris and her husband, Doug Emhoff, will participate in the annual commemoration at the National September 11 Memorial and Museum in lower Manhattan.

First lady Jill Biden will lay a wreath at the 9/11 memorial at the Pentagon.

Terrorists hijacked commercial airplanes on Sept. 11, 2001, and flew them into the Twin Towers in New York’s financial district and the Pentagon in Arlington, Virginia. A fourth plane crashed in a field in Shanksville, Pennsylvania, after passengers fought back.

Nearly 3,000 people were killed in the attacks. Biden was a U.S. senator at the time.

The White House did not announce which official will participate in the Pennsylvania observance.

• Associated Press News Researcher Jennifer Farrar in New York contributed to this report.